Holographic dark energy in Brans-Dicke cosmology with chameleon scalar field

TL;DR

This paper explores how holographic dark energy within Brans-Dicke cosmology, incorporating a chameleon scalar field, can produce phantom-like behavior and crossing of the equation of state in a non-flat universe.

Contribution

It introduces a model where a chameleon scalar field coupled with matter in Brans-Dicke gravity yields phantom crossing in holographic dark energy scenarios.

Findings

Phantom crossing can be achieved with parameter tuning.

Chameleon scalar field enables phantom-like equation of state.

Non-flat universe context is essential for the results.

Abstract

We study a cosmological implication of holographic dark energy in the Brans-Dicke gravity. We employ the holographic model of dark energy to obtain the equation of state for the holographic energy density in non-flat (closed) universe enclosed by the event horizon measured from the sphere of horizon named $L$. Our analysis shows that one can obtain the phantom crossing scenario if the model parameter $\alpha$ (of order unity) is tuned accordingly. Moreover, this behavior is achieved by treating the Brans-Dicke scalar field as a Chameleon scalar field and taking a non-minimal coupling of the scalar field with matter. Hence one can generate phantom-like equation of state from a holographic dark energy model in non-flat universe in the Brans-Dicke cosmology framework.